


The Transitive Property

by irena_adler



Series: Watson [13]
Category: Numb3rs
Genre: M/M, Sibling Incest
Language: English
Status: Completed
Published: 2016-01-05
Updated: 2016-01-08
Packaged: 2018-05-11 22:32:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 8,691
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5644249
Author URL: https://archiveofourown.org/users/irena_adler/pseuds/irena_adler
Summary: <blockquote class="userstuff">
              <p>Don and Charlie squabble over their favorite toy - David.</p><p>(Please note where this fic is in the series, before It Changes Everything)</p>
            </blockquote>





	1. Three's a crowd?

Originally published: 11/18/06 

**Title:** The transitive property, Part 1 **  
**Pairing: David/Don/Charlie **  
**Rating: FRAO (NC-17) **  
**Summary: Don and Charlie squabble over their favorite toy - David  
Part 1 - Three's a crowd?  
Don's plan and Charlie's plan collide.  
**Warnings:  Slash, M/M/M, incest.  Do not read if you are a minor.**  
**Disclaimer:** Not my characters, not my world, making no money. **  
**Feedback: Yes, please! Feed the author! **  
A/N:** Here is the long promised David/Don/Charlie threeway! This takes place after "The New Gravity" and before "Wrestling." It will probably be five parts.  Thanks to Emilia for being my enthusiastic first reader.

  


Part 1 – Three’s a crowd?

  


David Sinclair pressed his lips together and concentrated on not laughing.

“I didn’t know you were going to be here,” Charles Eppes was saying, his hands on his hips.

“Oh, it’s a murder investigation,” Don Eppes said snidely.“How odd for me to be here.”

The three of them were standing in a hotel room, far away from downtown LA.It was a generic hotel room in a typical three-story hotel in an unremarkable city along the highway.What made this room special was its perfect line-of-sight into another hotel room where a suspected killer had holed up.The camera with its infrared sights and motion detector were already set up and focused at that other room, chairs set around the camera in preparation for a long night.

That doesn’t mean David didn’t make sure that this room had a king-sized bed and lots of extra towels.His overnight bag bulged with condoms, lubricant, and a few sex toys he was going to try out on Don.Then there had come a knock on the door.David and Don had looked at each other, confirming that neither had called for room service, and drawn their guns.It was hard to say who had been more surprised when Don opened the door --Charlie, upon seeing Don and his ready gun, or Don, upon seeing his little brother appear at a random distant stakeout.David had found the looks on their faces hilarious, though he had no idea what was going on.

Don and Charlie stood now, eyeing each other, as David silently closed the door behind Charlie.He and Don holstered their guns.

“I was given to understand that David was doing this stakeout,” Charlie said grumpily.

“You don’t do stakeouts on your own.There are always at least two people,” Don responded.

Charlie turned to David.“When you told me about the stakeout, I thought it was an invitation.It wasn’t?”

“I didn’t tell you where it was,” David said, startled.

“Yeah, but the address was right there on your desk, with the room number and everything.”Charlie looked frustrated.“I thought …”

“Are you trying to jeopardize this whole investigation?”Don snapped.

Turning back to Don, Charlie raised his chin.“I was really careful and did all the undercover things.”

“You’re not a professional, Charlie.”Don said. “Why do you keep acting like it?”

“And how professional was it that you made this stakeout you and David?Really subtle.”

Don ran his hand over his hair.“I work with him all the time, there’s nothing unusual about it.”

“I wonder what Megan will think when she sees you only rented out one room.”

“She’ll think I’m being thrifty,” Don snapped. “Besides, she isn’t going to see the expense report.”

“I thought she typed up all of your reports,” Charlie needled.

Don rolled his eyes.“Oh, don’t you try and pin that old chauvinism thing on me, I write my own reports.And if I did ask another agent to help me, it wouldn’t be because she’s the only woman on my team.”

“Interesting, that.”Charlie said with a little toss of his head.“The only woman on your team never seems to be on stakeouts with you.Maybe because people would wonder?Now, with another guy, that’s perfectly safe.”

“It would have been if you hadn’t come traipsing down here,” Don replied.

“I don’t count driving seventy-three minutes as ‘traipsing’.”

“Boys, boys,” David said, unable to completely hide the laughter in his voice.“There’s no reason to bicker.”

“Weren’t bickering,” Charlie said.

“Having a reasoned discussion,” Don added.

“Still, there’s plenty of me to go around,” David said.

“Oh,” Charlie said, “I can see it now.I’d get seconds.”

“It’s only appropriate that I get him first, I’m the oldest,” Don said, with a superior expression.

“Only in chronological years, definitely not in brainpower,” Charlie responded.

“Older that you in maturity, no doubt.I made plans to get David to myself and you’re the one who busted in.”

Don and Charlie were now standing toe-to-toe in the middle of the hotel room, glaring at each other.David decided that this was getting too heated.

“Okay, Okay,” David broke in.“How about this …” _Here goes nothing._ “How about sharing me, at the same time?”

Charlie and Don stared at him.

“At the same time?”Charlie asked, his eyebrows shooting up.

“Eww,” Don agreed.

“I’m not talking about a three-way,” David said hastily, “Just a one-to-one-to-one-way.”

Charlie frowned and Don scratched his chin.

_They’re actually thinking about it,_ David realized.He hoped he was hiding his eagerness well enough.It’s not often you get the chance to experience one of your wildest fantasies.

Don looked at Charlie and Charlie looked at Don, then they both gave identical half-shrugs.

“Okay,” Charlie said.

“We can give it a try,” Don said cautiously.

_Thank you, God._ David smiled widely and went to bring the rest of the stuff from the car while Don tested the infrared camera.

When he came back into the hotel room, Charlie and Don were talking earnestly over the camera about focal lengths and optimum viewing radius.Their earlier antagonism seemed to have vanished.

Not for the first time, David wondered what it would be like to have a brother who always cared for you no matter what stupid thing you said or did.Well, that was wishful thinking and he had a fantasy here, waiting for him to take it.He was determined to show the Eppes brothers the time of their life.

David watched Charlie’s animated face and quick hands as he tried to explain something completely esoteric to Don.Don’s face had the patient but slightly exasperated expression that he often wore around Charlie.They were so different and so much alike.And both completely delicious.

The first time that David met Charlie, the first time that Charlie the genius had opened his mouth, David had gotten the overwhelming urge to tie Charlie down and do terrible things to him.To drive all intelligence out of those big brown eyes and replace it with mindless passion.Charlie’s slim, boyish body called to David in entirely unexpected ways.

Don, now, he hadn’t noticed right away, since he was so busy trying to impress him as a boss.The first time he’d noticed Don in a sexual way was one Saturday afternoon, when Don had been called in from playing basketball.There hadn’t been time for a shower, and Don had come to the crime scene wearing shorts and a sweaty T-shirt.David had found himself mesmerized by Don’s sweet ass and firm arms.From that moment on, a small part of his brain had always watched Don, fantasized about Don.He knew that Don, being a macho bastard, would never give in to David willingly.He’d have to ask in just the right way, with just the right persuasion.

Then Colby had arrived at the office, instantly grabbing David’s attention.Colby’s muscular body just screamed to be stroked, his round ass put on earth to be fucked.David had started planning his seduction of Colby that very day.

Then Colby had lead to Don and Don to Charlie …All three were incredible in their own way – Colby had amazing strength and stamina, Don was intense and creative and up for anything David could imagine, Charlie soaked up sexual experience like a sponge and gave it back tenfold.David had initiated each one into the world of sex with men and he’d gotten an incredible return on investment.

_Life is good._

__

____

__

__

___ _


	2. Round one

**Summary for the Chapter:**

> Don and Charlie chose sides.

**Title:** The transitive property, Part 2 **  
Pairing:**

David/Don/Charlie

 **  
Rating:** FRAO (NC-17) **  
Summary:** Don and Charlie squabble over their favorite toy - David  
Part 2 - Round One  
Don and Charlie chose sides.  
 **Warnings:  Slash, M/M/M, incest.  Do not read if you are a minor.**  
 **Disclaimer:** Not my characters, not my world, making no money. **  
Feedback:** Yes, please! Feed the author! **  
A/N:** Here is the long promised David/Don/Charlie threeway! This takes place after "The New Gravity" and before "Wrestling." It will probably be five parts.  Thanks to Emilia for being my enthusiastic first reader.  


 

David came up behind Charlie and Don and touched both lightly on the back.Charlie jumped, as if he forgotten all about David and why he had come.

Don checked the camera once again, making sure the motion detector would tell them if their suspect stirred from watching TV.

_I love those cameras,_ David thought. _Make stakeouts a lot more fun._

Don turned, stepped close to David and took David’s chin in his hand.He kissed him warmly, possessively.David kissed him back, sliding his hand around Don’s neck.Don’s other hand ran down David’s back to his ass then to his hips.Don’s whole body said, _this is my territory._ It was quite different to Don’s usual playful kisses.Charlie being here had obviously triggered Don’s jealousy. _No one owns me, Eppes,_ David felt like saying, but for the moment, with Don’s body against his, David didn’t mind

Don broke away and sat on a nearby chair to take off his shoes.David turned to Charlie.Charlie quickly came into his arms for his own kiss, equally possessive. _Interesting …_

David had always been good at figuring out what lovers wanted and giving it to them.Colby liked quick furtive gropings in places where they might get caught or marathon fucking sessions followed by a lot of cuddling.Don liked physical foreplay and new sensations.Charlie liked it slow, with lots of dirty talk. _Now I’m going to have to figure out how to please both Eppes at once. Well, you say you like a challenge …_

Smiling in anticipation, David pulled away and began unbuttoning his shirt.

Charlie stood and fidgeted, looking at Don until Don looked up.

“You know we gotta sometime,” Charlie said uncomfortably.

“Yeah,” Don grimaced.“No peck.A real kiss.”

Don stood up.He and Charlie leaned towards each other and their lips met.David’s cock jolted into life at the sight.Don slid his hand up Charlie’s cheek and Charlie laid his hand on Don’s shoulder.They kissed tentatively, like inexperienced teenagers.Don’s tongue flickered out and Charlie opened his lips.They kissed for another moment then drew back.

“Eh,” Don said with a half-shrug.

“Eh,” Charlie agreed.

“Now that we’ve got that out of the way,” Don said and they both turned towards David, obviously planning on forgetting about the other and concentrating on David.

David swallowed his disappointment.One of his darkest, deepest fantasies was watching the Eppes brothers fuck.Watching Don shove his thick cock up Charlie’s slim ass, hearing Charlie moan out his brother’s name.It would be incredible to see them fuck, but it was probably just as well.Things like that only worked in fantasies, reality was much less forgiving.

David finished unbuttoning his shirt and moved towards Charlie.He pulled up Charlie’s t-shirt and slid his hands underneath.He felt Don’s hands tugging his shirt out from his waistband then Don’s hands were warm on his back.

By unspoken agreement, the three of them decided to speed things up and quickly removed the remainder of their clothes.Don and Charlie did a brief visual assessment of the other’s body.David was relieved to note that neither seemed to mind what he saw.They could have easily turned skittish at this point.Now he needed to draw them both into bed.

Taking Don’s hand, David moved to side of the bed.He pulled Don close and rubbed full-length against him. “So what do you say, boss,” David said, his hands molding Don’s muscular body against own.“We wouldn’t want to waste the taxpayers’ money on a bed by not using it.”

“Waste not …” Don said, and pushed David down to the mattress.David grinned and scooted over for Don to climb on to the bed next to him.David reached for Don and Don for him and their mouths met, kissing slowly but hungrily.

Still kissing, David lay down, Don at his left side.David enjoyed Don’s delicious mouth for a long moment before that mouth began making its way down David’s neck and chest.Don’s tongue found David’s left nipple and David briefly forgot everything else as Don sucked and pulled at the nipple, giving it just the right amount of stimulation that pushed up against the border of pain but never went over.David groaned in appreciation, his eyes fluttering closed.

Don straightened up and shifted further down the bed, giving David a brief respite.David opened his eyes again and found Charlie.The younger brother was sitting on the edge of the bed, looking uncertain.

“Come here, baby,” David said warmly, holding out his right hand.

Don raised his head and looked at Charlie, obviously waiting for Charlie to object to the nickname.

Charlie just smiled and crawled up the bed to David’s right side.

“If I called you baby,” Don said, “you’d hit me.”

“It sounds different when he says it,” Charlie said and leaned over to kiss David’s chest.

David gave Don a slow smile.Don responded with a somewhat bemused look then returned to his pleasurable torment of David’s skin with mouth and fingers.His mouth reached David’s cock and David sucked in a breath.

At that moment, the camera beeped.All three of them groaned.

“Charlie, you check it,” Don said and David could feel Don’s voice vibrating against his cock.

Charlie grumbled but got up from the bed.He walked over to the camera and checked the infrared readout.“Just a cat or skunk or something in the bushes outside the room.”He fiddled with the sensitivity.

Don took full advantage of Charlie’s absence, straddling David’s hips with his knees and leaning down to suck David’s cock all the way down his throat.

David moaned softly.He remembered when he’d taught Don how to do that. _Quick learner._

“Hey,” Charlie demanded, getting back onto the bed.“Go back on your own side.”

David laughed.“Splitting me into two, hmm?”

Don lifted his head, sliding David’s cock out of his mouth with just the barest hint of teeth.David shuddered.Don licked David’s cock from base to tip.

“Donnie?” Charlie said petulantly.

“Okay, okay.” Don crawled off and lay back against David’s left side.

“Does that mean we each get half of your asshole?” Charlie asked blithely, rolling up against David’s right side.Charlie’s cock was hard where he rubbed it against David’s hip.

“What good is half an asshole?” Don complained. __

_Whoa, that gives me an idea,_ David thought. _Better hold off on that for now though._

Don’s cock was hard against David’s other hip and David wondered if they were really as uninterested in their kiss and the other’s naked body as they acted.

David looked back and forth between the two men and smiled.“Scoot down a little, both of you?”

They obliged while David sat up and turned around so that his head was near Don and Charlie’s pelvises and his was near theirs.Don and Charlie’s mouths moved in quickly to claim David’s cock, their noses bumping in their haste.After a brief moment of grumbling, they got themselves sorted out and David was treated to the wonderful feel of two tongues swirling over his cock, two mouths sucking on the nerve-rich skin.

Murmuring happily, David reached out to both sides and took hold of Don and Charlie’s waiting cocks.He held one Eppes cock in each hand and slowly stroked them up and down.It was surprising, given their different builds, how similar their throbbing cocks felt.A one-handed hand job was tough, especially with his left hand and both elbows jammed to his sides, but he remembered a few tricks and soon had both Eppes boys sighing with pleasure.Turning his head, he licked the head of one cock then the other, reveling in the taste of both man’s salty sweat and pre-cum as they mingled in his mouth.

Feeling the mouths leave his own cock, David looked up to see Don and Charlie leaning close for a kiss.Their hands moved on David’s cock in unison as their lips met.

This kiss was quite different from their first.Before they’d been tentative, self-conscious.Now there was no thought involved.They kissed with the lust and passion and the energy from their aroused bodies.David soaked in the sight of them exploring each other’s mouths, their lips welded together, their joined hands stroking David’s aching cock. Don buried his free hand in Charlie’s hair and Charlie’s free hand gripped Don’s arm.

David felt the cocks in his own hands twitch and he returned to his task.He worked those throbbing cocks with mouth and thumbs and tongue and fingers, even flicking them lightly against his cheek.Charlie was whimpering and Don moaning but they kept kissing, their sounds echoing inside their sealed mouths.

Charlie’s whimpers suddenly switched higher and David backed off on Charlie’s cock for a moment while he worked Don up to join him.Soon Don was almost ready and David brought Charlie back to fever pitch.First Don then Charlie began to rock his pelvis against David’s hands then with a dual moan, both men unloaded over David’s face.The hot splash of cum hit David’s cheeks, shooting across his mouth and nose and chin.David held both cocks to his mouth and lapped up spurts of cum as Don and Charlie shuddered over and over, their bodies trembling against David’s sides.Their hands gripped David’s cock uncomfortably tight but David welcomed the pain, since it allowed him to back a tiny bit away from his own orgasm.

Finally Don and Charlie stopped thrusting against David’s mouth and broke their kiss, gasping madly.David licked clean the head of each cock before letting it slide from his grasp. Charlie was rubbing his cheek unconsciously against David’s thigh.Don laid his head on David’s hip.

“Hey Chuck,” Don mumbled.“Not done here.”

“Oo,” Charlie said and took his hand from David’s cock to replace it once again with his clever mouth.Don’s mouth joined him and he moved his hand to tug on David’s balls.Charlie slid his hand under David’s ass to squeeze his ass cheek in rhythm to his licks.

David lifted his head so he could see better.He wanted to forever watch their mouths wrapped around his cock, watch as they chased each other up and down, licking him to impossible hardness.But his self-control was slipping, his eyesight going grey around the edges.His head fell back against the bed and he gave into his body’s screaming demands.

His back arched and then he was writhing against those hot mouths.They held him against the mattress and one mouth sucked the head of his cock in and the other fastened on that sensitive ridge below the head.

“Charlie Don Charlie Don,” David moaned incoherently, his brain and body on overload.The orgasm rose from his toes and exploded out his cock.He pumped against those mouths and they held on tight until he was spent and exhausted.

He looked up blearily to see it was Don who was licking cum from his lips and Charlie who was gently mouthing the base of his tingling cock.

David’s head flopped back down again.He really should do something about the cum covering his face before it got dry.But for a long moment, he just stared at the ceiling, floating in the afterglow, listening to Don and Charlie trying to get their own breathing under control.

David grinned. _An excellent start._ “Round one ended in a knockout,” he said cheerfully.

“Who won?”Charlie asked.   


"I think I did," David laughed.  


  



	3. Eager learners

**Summary for the Chapter:**

> Don and Charlie show their teacher - and each other - what they've learned.

**Title:** The transitive property, Part 3 **  
**Pairing:David/Don/Charlie **  
**Rating: FRAO (NC-17) **  
**Summary: Don and Charlie squabble over their favorite toy - David  
Part 3 - Eager learners  
Don and Charlie show their teacher - and each other - what they've learned.  
**Warnings:  Slash, M/M/M, incest.  Do not read if you are a minor.**  
**Disclaimer:** Not my characters, not my world, making no money. **  
**Feedback: Yes, please! Feed the author! **  
**

  
**A/N:** Here is the long promised David/Don/Charlie threeway! This takes place after "The New Gravity" and before "Wrestling." It will probably be five parts.  Thanks to Emilia for being my enthusiastic first reader.

 

David untangled himself and rolled off the bed.Grabbing a towel from the bathroom, he wiped his face.

Walking back into the room, he stopped short and watched a naked Don and Charlie leisurely touching each other.Don’s hand ran down Charlie’s surprisingly hairy chest as Charlie’s fingers traced the shape of Don’s mouth.

David’s recently spent cock woke up and began pulsing. _God, they’re sexy together._

It wasn’t just the illicitness of sex between two brothers, though that was a big part of it.The two men were also both so intense and focused, with immense hidden sexual depths.Their bodies were a lovely contrast in physical build, though similarities occasionally caught the eye.

Charlie looked up and noticed David watching them and reached out for the towel.Don rolled onto his back.David would have happily watched the two touch each other for the next hour but it looked like he was wanted back in the middle.

First David went over to the camera and checked their suspect.Looked like the man had fallen asleep, or else he liked to watch infomercials. _Oh good, no unpleasant interruptions._ He gave a silent thank-you to whoever in the Bureau had authorized the purchase of these pricy cameras and turned back to the bed.

David climbed onto the bed and into the space the brothers had created between themselves.He sat cross-legged and put one hand on each Eppes chest.Lifting his hands, he started at the top, touching both men on their forehead, drawing a finger across their eyebrows, eyes, nose.Every point of similarity sent a thrill through him. _Brothers._ _Brothers, brothers, brothers._ He swallowed, his throat tight with excitement. _Illegal in most places, taboo in pretty much every society throughout history._ He never thought he'd be able to watch this, see this happen. It was so wrong, so very wrong, and he knew it - had always known it. That didn't mean these two brothers together wasn't hot as hell.

David’s hands reached their mouths and, as his fingers were sucked into both shapely mouths, he forgot about anything other than the men on the bed with him.Don’s hand slid down David’s leg and he sucked hard on David’s right-hand fingers.On the other side, Charlie was twining his tongue around David’s left-hand fingers with a slow sensual touch as his hand trailed up David’s ribs.

David retrieved his fingers from their mouths and drew wet trails down their necks.Reaching their chests, he ran his fingers through their chest hair, amused again by how Charlie was more furry than Don.

Both Charlie and Don were lazily watching David’s face as he drew circles on their chests. _Time to wake you up again._ David smiled and took one nipple in each hand and began to toy with it.Dual sucked-in breaths.Don’s hand slid over David’s thigh and brushed a light touch across David’s hardening cock.Charlie’s hand strained to reach David’s nearest nipple.David leaned over slightly and Charlie gripped David’s left nipple between thumb and forefinger.He rubbed it as David did his, mirroring David’s touch, learning as he went.David switched to the men’s other nipples and brought them to hardness.Charlie was really starting to get good at that and David leaned into Charlie’s touch.

As if he thought David was forgetting about him, Don began stroking David’s cock more firmly.Pulling his hand back, Don rolled over on his stomach, scooted over, and buried his face in David’s lap.Don’s sensual lips slid over the head of David’s cock and David groaned.Don returned to the deep throating he’d been doing earlier before Charlie interrupted and David had to release Charlie’s nipple for the more solid shape of Charlie’s cock.He stroked Charlie almost roughly and his other hand gripped Don’s hair.

With Don’s throat squeezing his cock, it was hard for David to think but he better think now before it was too late. _Where to go from here?_ The Eppes brothers were willing to be directed by him, at least to a point. _Choices, choices._ The possibilities made him dizzy.He had the sex toys he’d brought, but there was one thing that he’d regret if it didn’t do it tonight.

David tugged on Don’s hair and Don reluctantly lifted his head.David grinned at him.“That mouth of yours is dangerous, Eppes.”

Grinning back, Don sat up and rolled his neck around on his shoulders.David released Charlie’s cock and climbed off the bed.David took a deep breath to restore his equilibrium.The Eppes brothers were working him as much as he was them.

He reached over to his bag on the side table and pulled out lube and a condom.He rolled the condom quickly over his hard cock and turned back to the bed.

“Move over, baby,” David said huskily.“You need fucking.”

Charlie smirked.“Oh I do, do I?”

“Yes,” David said, climbing onto the bed and pulling Charlie close.“It’s been too long since your tasty ass got pounded, too long since my hard cock buried deep inside you, making you whimper and plead for more.”

“Yesss,” Charlie said, his smirk gone to be replaced by lustful anticipation.

“Tell me what you want, baby,” David demanded.

“Fuck me, David,” Charlie begged.“Fuck me slow and hard.”

“That’s right, my little slut,” David purred.“My sweet little math slut, spread yourself for me.”

Charlie turned over and got to his hands and knees.His posture was totally open and uninhibited, his face towards Don, his ass in position for anything David wanted to do to him.

David licked his lips and looked over at Don who’d been watching and listening.Don’s eyes were dark and his hand was on his cock, leisurely stroking.David smiled, knowing that Don was enjoying the show, whether he admitted it or not.

David turned back to Charlie.“You want my cock inside you, my little slut?”

Charlie shivered.“God, yes, please.”

David squeezed some lube on his index finger.“Do you think you deserve that?”David pressed his slick finger against Charlie’s tight asshole.“Or maybe I’ll just fuck you with my fingers until you can’t take anymore and shoot your load all over the bed.”David pushed his finger inside.

Charlie whimpered.“Fuck me, please.”

David slid a second finger inside, stretching Charlie slowly.“I am fucking you, baby,” he said, moving his fingers in an unhurried fashion.

“Please, with your cock, _please_ ,” Charlie said, practically wailing.

The anguished plea sent a shiver through David.“My sweet slut wants it bad.”

“Been too long,” Charlie said, his breath coming fast.“I want it, I _need_ it.”

David grinned.What a long way Charlie had come in such a short time.“Okay, baby,” David said soothingly, “I won’t make you wait any more.”

“Please,” Charlie whimpered again.

David got to his knees behind Charlie and pressed his cock against that waiting asshole.He pushed his way slowly inside and Charlie moaned in appreciation.Charlie’s head dropped down between his shoulders.His knees shifted farther apart, as if he could welcome David even more than he was.

“Yes, my sweet baby,” David said in approval.“That’s good.Oh, that’s good.”

David stroked Charlie’s ass, slow like Charlie liked it.He could never get enough of Charlie’s slim ass.It might not be as sexy as Don’s or luscious as Colby’s, but there was just something in the way it gripped his cock, the way it held off his orgasm until David thought he would die from the strain.If he had to choose just one hole to fuck for the rest of his life, Charlie’s asshole would be a leading candidate.Don’s mouth would be a close second.

Running his palm up and down Charlie’s hips, David looked over to Don.Don was watching them, his eyes hooded, his lips parted.He was stroking his cock in perfect rhythm to David’s thrusts.

_God, if you could only feel your brother’s ass …_ David thought. _But I’ll happily fuck him for you._

Charlie was also looking at Don.Shyly, Charlie reached over and touched Don’s hand.Don hesitated then let Charlie replace his hand on his cock.Charlie tugged him closer and began to stroke that thick cock from base to head.Don leaned back, his eyes on Charlie.

Licking his lips, Charlie looked up at Don.Don swallowed then gave a short nod.He scooted even closer and Charlie took Don’s cock into his mouth.Don threw his head back and a soft groan escaped his lips.

David’s whole body throbbed at the incredible sight of Charlie’s curly head bent over his brother’s hard cock.David reached down and pulled Charlie’s hair aside, so he could watch that sensitive mouth slide over Don’s pulsing organ, see Charlie’s hand pull gently on Don’s balls.

“Damn,” Don gasped.“You’re not too bad at that.”  
  
David had to grin.“My baby is an enthusiastic learner.”

Don nodded and closed his eyes.David didn’t think it was to shut out the view of who was between his legs, but rather to completely enjoy the sensations Charlie was giving him.

David let go of Charlie’s hair and returned to sliding his cock in and out of Charlie’s sweet ass.He leaned over and took a firm grip on Charlie’s cock.He wasn’t at all surprised to find Charlie hard and twitching with the dual arousal of David’s cock in his ass and Don’s cock in his mouth.David stroked Charlie’s cock and Charlie whimpered in gratitude.

For a moment, the room was full of the sounds of soft gasps, wet slurps, and the slick sound of lubricant sliding over skin.

Abruptly, Don’s eyes flew open.“Charlie,” Don said, his voice strained.“You better stop that or …” His voice trailed off into a moan.He tried weakly to push Charlie away but Charlie would have none of it.Charlie’s mouth powered up and down Don’s cock, sucking him as deep as he could.

“Charlie, you have to … _shit_ …” Don grabbed hold of Charlie’s hair and slammed his hips upward, plunging himself even deeper into Charlie’s eager mouth.

David stroked Charlie’s rigid cock in time to Don’s wild thrusts. Charlie soon shuddered and came, moaning around Don’s cock while his cum shot over David’s hand and the bed underneath him.

Before Charlie had stopped, Don moaned and let loose.Charlie swallowed his cum fervently, like a thirsty man at a water fountain.David watched Charlie’s throat muscles work as he tried to take in all of Don’s cum.Some still slid out between Charlie’s lips and the sight of Don’s cum dripping down Charlie’s chin was the last straw for David.

David gripped Charlie’s hips and slammed into him, Charlie’s slim ass welcoming everything that David dished out.He rode him to orgasm, Charlie grunting with pleasure, his mouth still around his brother’s cock.David pounded Charlie up to, through, and well beyond his orgasm, not wanting to stop.Finally David’s cock was too soft and sensitive and David slid out and collapsed on the bed.

Charlie rolled over and collapsed next to him, laughing with delight.

David groaned in satisfaction.“Charlie, baby, you are the sweetest fuck I have ever had.”David was looking at Don when he spoke so noticed the dark look that passed over Don’s face.He bit back a sigh.The Eppes boys were ridiculously competitive. 

David grinned at Don. “Too bad that ass is nothing to look at.”

Don smiled sideways.“That’s true.”

“Hmph,” Charlie mumbled, but didn’t sound too put out.He was probably calculating just how many fucks that would make him better than. _Better take that number and revise it upwards._ David chuckled to himself.

Don blinked down at Charlie.“Umm, Charlie, you’ve got some … on your chin.”

Charlie wiped Don’s cum from his face.“Not too bad, eh?” he said triumphantly.

“Not too bad at all, Chuck,” Don gave him a slightly dazed smile.“Been getting in a lot of practice, eh?”

“I prefer to think of it as natural acuity.”Charlie looked smug.

 "I see," Don laughed.

  



	4. Noticing

**Summary for the Chapter:**

> David encourages Don to notice Charlie.

**Title:** The transitive property, Part 4 **  
**Pairing: David/Don/Charlie **  
**Rating: FRAO (NC-17) **  
**Summary: Don and Charlie squabble over their favorite toy - David  
Part 4 - Noticing  
David encourages Don to notice Charlie.  
**Warnings:  Slash, M/M/M, incest.  Do not read if you are a minor.**  
**Disclaimer:** Not my characters, not my world, making no money. **  
**Feedback: Yes, please! Feed the author!  


  
**A/N:** Here is the long promised David/Don/Charlie threeway! This takes place after "The New Gravity" and before "Wrestling." It will be five parts.  Thanks to Emilia for being my enthusiastic first reader.  


  


A longer break was called for this time.David disposed of his condom then dug a couple of cans of Coke out of the small ice-chest.He handed one to each of the others and popped one open for himself.

Don touched his ice-cold can to Charlie’s naked back and laughed when he jumped.

“I’d be careful,” Charlie said with an arch of his eyebrows.“You’re pretty exposed yourself.”

Don quickly moved to lay flat on his stomach and both David and Charlie laughed.

They sipped their sodas in silence for a moment.Charlie licked his lips and David smiled. _I wonder if Charlie likes the combination of Coke and cum as much as I do._

“So what are you guys doing up here, anyway?”Charlie asked.“Other than the obvious sex part.”

As Don explained the basic outlines of their case against the man in the other hotel room, David and got up from the bed.He checked on the camera to make sure that the man was still in the same place as they left him.According to the infrared readout, he was probably asleep.David couldn’t help but wonder what the infrared meter would have registered if it had been pointed at this room a few moments ago. _We probably would have broken it …_

Turning back, David watched Don and Charlie talk, like he had so many times before.If he closed his eyes, he could imagine that they were in the office, standing by a whiteboard.He kept his eyes open and enjoyed watching their bodies. _If I could just take these two home and keep them in my basement …_ David grinned to himself at the image that conjured up.

Don finished telling Charlie about the case and Charlie thought for a moment then shrugged, obviously dismissing it as uninteresting from a math point of view.

Charlie’s eyes moved to David, and he looked David’s body up and down.

David turned around in a circle then asked, “Like what you see?”

“Always,” Charlie said earnestly and David laughed.David made a “how about you” gesture at Don who nodded in agreement.

“Now that we’re done with the rest and the mutual admiration,” David said, climbing onto the bed.“What next?”He had his own ideas but was open to suggestions.He put a hand on each Eppes, his touch light and teasing.

Charlie looked thoughtful then said, “It’s my turn to fuck David.”

Don frowned and slid his hand over David’s ass.“What makes you think that?I bet you’ve been with him more recently.”

“Yeah, but you had that whole week when you were after that bank robber.”

Don moved closer to David.“So, that was months ago.”

“Still counts.”

David laughed at the sight of the two brothers squabbling over who would fuck him.“Didn’t your mom ever teach you to share?”

“I did share,” Don snapped, a strange anger coming to the surface.“You were mine first, remember?”

“Oh, trying to claim ownership by _prima facie_.”Charlie shot back.“That doesn’t even hold up in most courtrooms.”

“This doesn’t look like a courtroom.”

“No, it looks like—“

David cleared his throat.“How about both of you at once?” _I’ve always wanted to try that._

Don and Charlie stared at him.

“Is that even possible?” Charlie asked.

“Yeah,” David said, trying to sound confident.“I’ll just need lots of warm-up.”

“Okay, well, that’s solved then,” Charlie said with relief.

Don stared at Charlie for a moment, then with a shrug and a smile that felt somewhat forced said, “Besides, the addition of you shouldn’t make much of a difference.”

“Humph,” Charlie said. “Just for that, I’m doing the warming-up thing.”

Don waved for Charlie to go ahead.

“Turn over,” Charlie commanded David.

David grinned at his bossy tone of voice and rolled over onto his stomach, presenting his ass for Charlie’s attentions.Charlie grabbed the bottle of lube and went quickly to work.He pressed his index finger into David’s ass and began to rub.

Wanting to banish that odd shadow from Don’s eyes, David smiled up at him.“C’mere, boss,” he said and Don moved close to David’s mouth.David kissed the inside of Don’s thighs, biting gently on the points where thighs met pelvis.David felt Don relax under his touch.Don closed his eyes and a shiver went through him.

Opening his eyes, Don smiled down at David and David wondered again if he had imagined the shadow.“I’m gonna be thinking about this at your next performance review, Sinclair,” Don teased.“Better make it good.”

“As you say, boss,” David grinned and took both of Don’s balls into his mouth, earning a startled groan from Don.Very gently, David sucked and pulled until Don was gasping with the unusual sensation.David let the balls slide out of his mouth and went after the firm, muscular column of Don’s cock.

Charlie now had three fingers inside David’s ass and David was starting to feel pleasantly stretched.His lips against Don’s cock, David said, “Do four.”

“Four?”Charlie asked in astonishment.

“Mm-hmm,” David said, returning his attention to Don.He swirled his tongue around the head of Don’s cock.David heard the sound of more lube being squeezed out of the bottle and the touch of a fourth finger.It felt good. _More to come._

As David mouthed Don’s cock, he saw that Don’s eyes were resting on his brother, an expression of surprised lust on his face.

_Yes,_ David said silently. _Notice your little brother.Notice his lovely slim body, ripe for the taking.You know you want him.How could you not?And he wants you.It’s obvious in every movement he makes.He’s made all the overtures so far.His hand on your cock, his mouth on your cock._ David shivered with delight at the memory. _How about returning the favor? I know you like to suck cock.I know how eagerly you open your lips for me or Colby.Taste your brother.Feel what it’s like to melt that incredible brain into mindless animal passion._

As if David’s encouragements were being translated directly into Don’s skin, Don said, “Charlie,” his voice thick.He cleared his throat then said again, “Charlie?”

At Don’s odd tone of voice David lifted his head from Don’s cock and looked between the two brothers.

“Hmm?” Charlie asked.

Don said, “David’s not the only one going to need warming up.”

Charlie blinked at Don, uncomprehending.

Don moved around David and held out his hand.“Come here, dork.”

Charlie pulled his fingers out of David’s ass and wiped his hand on the sheet.Then he crawled slowly towards Don, as if unsure of his intentions.

Don reached down and pulled Charlie the rest of the way, bringing Charlie upright and hard against his body.Don claimed Charlie’s mouth, bending Charlie back with the force of his kiss.Charlie whimpered and melted against Don.Don held Charlie’s face with both hands and plundered his mouth.Charlie went completely boneless at the onslaught.

Don lifted his mouth from Charlie’s and covered Charlie’s face with rough kisses, then reclaimed Charlie’s warm mouth.

David realized that he was grinding his own cock against the mattress at the pulse-pounding sight.He stopped and sat up, not wanting to end things too quickly for himself.

Moving from Charlie’s mouth, Don leaned a pliant Charlie back and devoured his way down his long neck, across his furry chest.He took Charlie’s right nipple between his teeth and drew high-pitched gasps from Charlie’s lips.

Pulling away, Don released Charlie and Charlie fell with a whoof onto his back on the bed.Don’s mouth was quickly on Charlie’s stomach, making Charlie squirm with ticklish pleasure.

Don worked his way down Charlie’s body and Charlie’s wide eyes grew even wider. Don lifted his head and gave Charlie a gleeful smile.Then his mouth was on Charlie’s cock, rough and demanding.Charlie whimpered helplessly as Don worked over his cock and balls, his tongue and fingers everywhere, his touch utterly knowing.

Gasping himself, David had to pinch the end of his cock, the pain bringing him back from the precipice.He’d thought these two looked sexy together earlier, but that was nothing compared to watching Don consume Charlie.Don moved instinctively, understanding what his little brother would enjoy, what he would crave without even realizing it himself.

Abruptly, Charlie moaned and thrust himself against Don’s mouth.Don quickly lifted his head and Charlie mewled in protest.

“No, no,” Don said, with a smile of satisfaction at Charlie’s limp state.Limp everywhere except for his rod-straight cock, still glistening with Don’s saliva.“We’ve got other plans.”

Charlie mewled again, his hands grabbing at Don, trying to pull him back to him.Don leaned away, his eyes alight with triumph, his own cock rigid against his stomach.

David decided it was time for him to remind them he was here, if he ever wanted to fulfill the fantasy that his ass was all primed for.Any longer watching these two together and David wouldn’t be able to hold himself back.

He got their attention by the simple expedient of rolling off the bed and retrieving two condoms.When he turned back to the bed, he found both Eppes looking at him with interest.Charlie groggily sat up, gave Don a quick glare, then focused on David.Don smirked at the glare and scooted to the edge of the bed.They waited for David to direct them in this new experience.

_I love these two …_

David handed a condom to each man and watched with anticipation as they rolled the condoms down their hard cocks.

David arranged Don and Charlie so that they were sitting facing each other, their legs entwined, balls to balls.David took out the bottle of lube and, holding Don and Charlie’s cocks together at the base, drizzled a generous amount of lube over their mated cocks.David replaced his hand with Don’s, so that Don was now holding the cocks ready.David wiped his hands then climbed onto the bed.He crouched over their laps, facing Charlie.He gripped Charlie’s shoulders and took a deep breath.

Lowering himself slightly, David felt Don position the two cocks against his prepped asshole.Slowly, ever so slowly, David sank downwards, impaling himself on the joined shafts. His eyes grew wide and a groan escaped his lips.He felt like he was being split apart, just like the first time he’d gotten fucked.He bore down with his muscles, opening himself up wider.His fingers dug into Charlie’s shoulders and a hot flush spread across his body.His legs were trembling by the time he reached Don’s hand.Don pulled his hand away and David sank all the way down, two cocks buried up to the balls inside him.

Groaning softly, David closed his eyes and leaned back against Don’s chest.

“You okay?”Don asked, his voice a trifle strained.

“Yeah …” David groaned, desperate for motion but giving his body time to adjust.“You guys?”

“Tight,” Don said, “But good.”

“Yeah,” Charlie agreed.He wiggled his hips slightly and both Don and David gasped.Just that small movement inside those tight quarters set David’s body on fire.Don’s squeezed cock was rubbed hard between Charlie’s and the walls of David’s ass.

Don moved his hips and it was Charlie’s turn to gasp.Then Charlie returned the favor and all that was possible was for David to groan and hold on as the two cocks seesawed inside him.Every nerve in his ass was awake and roaring, his prostate tormented by every motion.

David tried to keep his eyes open, but the pleasure rushing through his body in alternating waves was too great.He felt his eyes roll back into his head and he could only rely on Don and Charlie to hold him up as his body shook and shuddered under the onslaught.

Charlie’s light touch on David’s cock was all David needed to explode.Spots appeared before his eyes as his cock spewed out hot cum in white ropes over Charlie’s hand and stomach.As he came, his muscles squeezed tighter in his already impossibly full ass and a prostate orgasm slammed through him on the heels of the one from his balls.As he shattered into a million orgasmic pieces, he distantly heard Charlie and Don groan then thrust up wildly into him.Overwhelmed, David blacked out for the merest instant then came back, the world still writhing in passion around him, voices in front and behind him raised in mutual fervor.

  
  



	5. Ground rules

**Summary for the Chapter:**

> Don and Charlie set some ground rules.

**Title:** The transitive property, Part 5 of 5  
**Pairing:** David/Don/Charlie **  
**Rating: FRAO (NC-17) **  
**Summary: Don and Charlie squabble over their favorite toy - David  
Part 5 - Ground Rules  
Don and Charlie set some ground rules.  
****Warnings:  Slash, M/M/M, incest.  Do not read if you are a minor.**  
** **Disclaimer:** Not my characters, not my world, making no money. ** **  
****Feedback: Yes, please! Feed the author!  


********

  
******A/N:** **** Here is the long promised David/Don/Charlie threeway! This takes place after "The New Gravity" and before "Wrestling."  Thanks to Emilia for being my enthusiastic first reader.  


  


  
Some moments later, David regained some sense of reality again.Someone was whimpering loudly and it took David a moment to realize it was him.

“David?” Charlie gasped.“You okay?”

“Kill me now,” David mumbled.“If it had been any better, I would be dead anyway.”

Don chuckled and David discovered he was collapsed against Don’s chest, his fingers still clenched on Charlie’s shoulders.David released his grip and grimaced.

“Probably gonna bruise, sorry,” he said to Charlie.

“Don’t mind,” Charlie said, rubbing his shoulders.“Was worth it.”

“Mm-hmm,” Don agreed.

The three of them sat in warm, exhausted silence for a while until Don and Charlie’s softening cocks slid out of David’s overstretched asshole.They untangled themselves from each other and lay down on the bed, David between Don and Charlie.For another long blissful moment, they just drifted in the afterglow of three incredible rounds of sex.

Eventually, Don stirred.He reached over David’s chest and lightly touched Charlie’s hand.“Charlie?”

“Hmm?” Charlie said sleepily.

“We need to … set some ground rules.”

“Yeah.”Charlie said, propping himself up on one elbow so he could see Don.“Yeah, we do.”

Don propped himself up in a mirror image of his brother and met his eyes.“First rule is no fucking, ever.”

“Agreed,” Charlie said.“That’s just too … I agree.”

“And the other rule is nothing when it’s just us, ok?Only with David … or some other third person.”

Charlie agreed with obvious relief.“Yes, never when it’s just us.You’re my brother and I don’t want to mess that up.”

“You’re always going to be my brother,” Don said with an exaggerated sigh. “No matter how much you screw up.”

“I generally prefer screwing down,” Charlie responded.

Don rolled his eyes.“I didn’t really need to know that.”

Charlie grinned.“Maybe it wasn’t a bad thing that I came up here tonight?”

For a moment, Don looked like he wanted to disagree.Then he grinned back and said, “No, _baby_ , it wasn’t.”

“Don’t you _dare_ start calling me baby!”Charlie glared at Don.“It sounds like … ‘infant’ when you say it.”

“I see,” Don laughed.“And what does it sound like when David says it?”

“Umm,” Charlie said, looking at David.

David rescued him.“It sounds like ‘you delicious sexy sweet thing.’”

Charlie blushed and nodded.

“Yuck,” Don said.“Okay, I won’t call you ‘baby.’”

“Good,” Charlie said.

“No problem, Chuckie.”

Charlie groaned and poked him in the shoulder.

David smiled.It looks like things were going to be okay between the two brothers.He’d enjoyed the activities hugely and would be thinking of it every time he sat down for the next week, but it wasn’t worth destroying Don and Charlie’s relationship.He would never forget the sight of Charlie’s mouth around Don’s cock or Don turning Charlie into a limp puddle.Tonight’s reality had far outstripped David’s fantasies.

Grumbling, Don and David left Charlie naked on the bed and cleaned themselves up then got dressed.They didn’t want to be chasing a suspect in the nude.David wasn’t surprised to discover that his ass was very sore, but it was a pleasant ache.

In the middle of buttoning up his shirt, David glanced over at Don.Don was looking at David with an odd expression. _Wistful?Resigned?_ Before David could be sure, the expression was gone and David wondered if he’d imagined it.

By the time they were clothed and settled into chairs to wait out the night, Charlie was asleep and snoring on the bed.Charlie lay sprawled out, his body completely exposed to the evening air and their eyes.The total naturalness and spontaneity of Charlie’s sexuality drew David and, it looked like, Don as well.

Don’s eyes as he turned to David were speculative.“I think we can give him a few minutes to rest and recover,” he said with a drawl.

David laughed and gingerly settled back into his chair.“Meanwhile, we can come up with fun ideas on how to wake him up.”

“He can be pretty hard to wake up,” Don warned.

“Oh goodie,” David grinned.“We’ve got ice … and more Coke.”

Don laughed then said, “Too bad Colby couldn’t be here.”

David’s eyes lit up at the thought.“Though I’m not sure the bed would be big enough.”

“I’m sure we’d manage,” Don said.“You can have Charlie and I get Colby.”

There was something about the way Don said that made David frown in thought.“Are you sure you’re okay, with …” He gestured at the sleeping Charlie.

“Oh sure,” Don said with a shrug, “What can it hurt?”

David looked at him but Don’s usual persona of confidence and competence had been securely put into place.David banished his unease.Whatever the ramifications of tonight were, Don could handle it.He was the strong, in control brother.David was more concerned about Charlie.He’d keep an eye on Charlie, a very close eye …

Smiling, David watched Charlie sleep and thought of ice and warm skin and Charlie’s soft little whimpers of passion.He hoped he’d brought enough condoms.

 


End file.
